Para-xylene (p-xylene) is an important intermediate in the production of terephthalic acid, a monomer used in the formation of polymers such as poly(ethylene terephthalate) (PET). Yet, traditional methods for the production of p-xylene suffer certain limitations. More specifically, p-xylene is commonly derived from petrochemical source materials having a negative environmental profile and subject to significant price fluctuations. Moreover, p-xylene is commonly prepared from processed petrochemical mixtures containing C8 aromatics, a complex and inefficient process given that p-xylene typically represents only from about 20% to about 25% of the mixture.
Bio-based plastics, or bioplastics, represent a new class of plastics made from biomass source materials, including food (e.g., corn) or non-food materials (e.g., starch-producing plants). Bioplastics offer environmental advantages compared to petroleum-based plastics, including the use of renewable materials and a more limited impact of greenhouse gas emissions. Bioplastics can also normally be produced using the existing manufacturing technology, more often than not using the same reactors and machinery.
PET is among the most commonly used plastics in packaging, particularly in the food and beverage industry. There has been increasing interest in developing PET packaging from biomass. Containers comprising PET derived from bio-based materials, or bio-PET, are disclosed in PCT Publication No. 2009/120457. Commercially available bio-PET packaging contains bio-derived ethylene glycol and petroleum-derived terephthalic acid.
There remains a need for the production of terephthalic acid and p-xylene from renewable biomass sources. There is a further need to provide bio-PET efficiently and cost-effectively using both bio-derived terephthalic acid and bio-derived ethylene glycol.